In today's wireless telecom scenarios, as technology such as Global System for Mobile Communications (GSM)/Universal Mobile Telecommunications System (UMTS)/long-term evolution (LTE) progress towards more efficient band utilization, there is also continuous need of maintaining a quality of services (QoS) with existing mobile features such as short message service (SMS), multimedia messaging service (MMS), Browsing, Emergency services, and so on. One of the important features is mobile originated (MO)/mobile terminated (MT) call. As per current implementation, there are cases, where user equipment (UE) can miss an MT call paging due to a state mismatch between the UE and a wireless communication network.
For example, a UE was registered initially for both circuit switched (CS) and evolved packet system (EPS) services with a mobility management entity (MME). If the UE reselects to a universal terrestrial radio access network (UTRAN)/GSM enhanced data rates for GSM evolution (EDGE) radio access network (GERAN) cell (also referred to as an intersystem change), but in a same location area identity (LAI) as a registered LAI. In this case the MM does not perform a location area update (LAU). Then a general packet radio service (GPRS) mobility management (GMM) initiates routing area update (RAU) and receives an RAU Reject due to a network failure at a serving GPRS support node (SGSN), and the GMM attempts to update its state and start timer T3302 (after an attempt counter has reached 5 failed attempts). The MM is assumes that it is in a registered area of a mobile switching center (MSC), and hence not performing the LAU, and even the GMM has failed to perform an RAU successfully. Hence, the context of the UE is not transferred from an S1 mode to an Iu/AGb mode. For the MME, the UE is still in its registered area. This results in a registration state mismatch between the UE and the wireless communication network. Further, if there is any MT paging for the UE, the MSC forwards the paging to the MME through a serving GPRS support (SGs) interface. The MME pages the UE in the LTE area, but the UE is actually in the UTRAN/GERAN area. Hence, the UE will miss the MT paging.
In another example, after the intersystem change from the S1 mode to an Iu mode or an A/Gb mode, even though the UE is in an MM registered area, the RAU was attempted. If GMM still fails to successfully register with the network due to an RAU reject from the wireless communication network (due to congestion, network failure at a serving GPRS support node (SGSN), and so on), the UE misses the MT Call paging.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.